1. Field of the Invention
The present invention relates generally to the testing of jet engines. More particularly, the present invention relates to testing a jet engine in an outdoor environment while substantially attenuating the noise caused by testing the jet engine.
2. Description of the Prior Art
Noise from jet engine testing can cause auditory health effect including hearing loss and deafness, as well as non-auditory health effects such hypertension and nervous disorders. This type of noise also disturbs sleep of individuals in proximity to the test site; affects the performance of children in school and decreases the value of real estate surrounding the test site. In addition, noise from jet engine testing is one of the most common sources of tensions between surrounding communities and military air bases, and the military needs to aggressively pursue any and all available means to reduce its impact.
Typical sound levels for noise varies from 60 dBA for normal conversation to 70 dBA for vacuum cleaner to 130 dBA or more for a jet engine at 100 feet. OSHA (Occupational Safety and Health Administration) regulations require that engineering controls be used or that personal protective equipment be provided for a worker exposed to sound levels greater than 85 dBA for more than 8 hours.
As military aircraft engines become more powerful and noisier, as aircraft operations expand, and as land areas proximate to military operational bases are developed for commercial and residential use, jet engine testing noise and other issues create substantial disagreement and tension between the military and local officials.
Thus, there is an urgent need to significantly reduce jet engine noise by up to 20 dBA during static testing of a jet engine. There is also a need to provide the military with a new state of the art device for testing jet engines which is relatively inexpensive and also brings jet engine ground noise limits within acceptable limits to surrounding communities.